1. The Field of the Invention
The present invention relates to connectors, sometimes referred to as DIP sockets, which are fixed to a printed circuit board and into which electronic packages known as dual in-line packages are removably plugged. Conductive contact members in the connectors or sockets transmit current between the DIP and PCB.
2. Prior Art
The present invention is a novel improvement and a departure from at least the following:
______________________________________ Patent No. Patentee Class/Subclass ______________________________________ 3,763,459 Millis 339/75 M 4,080,032 Cherian et al 339/75 M ______________________________________
A conflict has existed between the desired electrical conductivity between the contact members in a connector and the leads on a DIP and the amount of force required to insert the leads into the connector. Prior art connectors other than the two noted above traded low insertion forces for good electrical contact. The trade-off was logical in that as a general rule, once the DIP was inserted, it was seldom removed. Accordingly, good electrical performance was the primary and in some cases, the only parameter of interest.
The trade-off, however, is not acceptable in those connectors used for testing and evaluating integrated circuits and electronic components in the DIP. In this situation, DIP's are plugged into a connector, tested and then removed. In plants making DIP's for example, such testing is on an assembly line basis with a DIP's being plugged in, tested, and removed. Under these conditions, any but zero or low insertion forces would cause a time loss and a great many bent DIP leads. However, good electrical conductivity is still required. Workers in the field have been generally successful in achieving the best of two worlds: low or zero insertion forces plus good electrical conductivity. The two patents noted above are examples thereof. Connectors disclosed in both patents include means for opening double arm contact members so that the DIP leads may be easily inserted and removed. In Cherian et al, the contact members have two arms positioned transverse to the connector's longitudinal axis. The inside arms are latched to transversely moving members which are moved by a centrally located and longitudinally moving member via cooperating ramps. As the central member is moved, the transversely moving members pull the inside arms away from the outside arms so that the DIP may be inserted or removed.
In Millis, the connector or socket as referred to in his patent, is of a three piece layered construction with the middle member movable axially. The U-shaped contact members are positioned in the socket and extend up through openings in the middle and upper members. The openings in these members through which the arms extend have concave surfaces so upon moving the middle member, the concave surfaces curve the arms around the leads.